Peroxynitrite and fibrinolytic system-The effects of peroxynitrite on t-PA-induced plasmin activity

Anti-inflammatory and antioxidant actions of extracts from Rheum rhaponticum and Rheum rhabarbarum in human blood plasma and cells in vitro

Rheum rhaponticum L. (rhapontic rhubarb) and Rheum rhabarbarum L. (garden rhubarb) are edible and medicinal rhubarb species used for many centuries in traditional medicine. This work is focused on the biological activity of extracts from petioles and roots of R. rhaponticum and R. rhabarbarum as well as rhapontigenin and rhaponticin, typical stilbenes present in these rhubarbs, in a context of their effects on blood physiology and cardiovascular health. Anti-inflammatory properties of the examined substances were evaluated in human peripheral blood mononuclear cells (PBMCs) and THP1-ASC-GFP inflammasome reporter cells. Due to the coexistence of inflammation and oxidative stress in cardiovascular diseases, the study design included also antioxidant assays. This part of the work involved the assessment of the protective efficiency of the examined substances against the peroxynitrite-triggered damage to human blood plasma components, including fibrinogen, a protein of critical importance for blood clotting and maintaining the haemostatic balance. Pre-incubation of PBMCs with the examined substances (1-50 μg/mL) considerably decreased the synthesis of prostaglandin E2 as well as the release of pro-inflammatory cytokines (IL-2 and TNF-α) and metalloproteinase-9. A reduced level of secreted apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) specks in the THP-1-ASC-GFP cells was also observed. The examined substances significantly diminished the extent of ONOO‾induced oxidative modifications of blood plasma proteins and lipids and normalized, or even strengthened blood plasma antioxidant capacity. Furthermore, a reduction of oxidative damage to fibrinogen, including modifications of tyrosine and tryptophan residues along with the formation of protein aggregates was found.

Surface-enhanced Raman scattering-based detection of plasmin activity by specific peptide substrate

In this study, a new surface-enhanced Raman scattering (SERS)-based method has been developed for the detection of plasmin activity. Firstly, different peptide sequences, which are specific to plasmin, were examined. Then, SERS substrates were prepared by chosen peptide substrate. Enzyme activity was determined by pursuing the reduction of DTNB band at 1331 cm^-1 with Raman spectroscopy. The reduction in SERS intensity was related to the plasmin activity, and changes in SERS intensity vs. plasmin concentration graph was obtained. Limit of detection (LOD) and limit of quantification (LOQ) values were calculated as 2.14 U/mL and 6.42 U/mL, respectively. Intra- and inter-day repeatability results were determined as 1.45% and 1.47% relative standard deviation (RSD). Also, recovery of the method was determined for the plasmin spiked milk samples. The results demonstrated that the proposed method could be successfully used to detect the plasmin activity in milk samples.

Comparison of Phenolic Metabolites in Purified Extracts of Three Wild-Growing Herniaria L. Species and Their Antioxidant and Anti-Inflammatory Activities In Vitro

The work is aimed at phytochemical characterization and In Vitro evaluation of antioxidant actions, anti-inflammatory effects, and cytotoxicity of purified extracts from three rupturewort (Herniaria L.) species, i.e., Herniaria glabra (HG), H. polygama (HP), and H. incana herb (HIh). The total phenolic content established in the purified extracts (PEs) of HIh, HP, and HG was 29.6, 24.0, and 13.0%, respectively. Thirty-eight non-saponin metabolites were identified using LC-HR-QTOF-ESI-MS; however, only 9 were common for the studied Herniaria species. The most abundant phenolic compound in HG-PE was narcissin (7.4%), HP-PE shared 3 major constituents, namely cis-2-hydroxy-4-methoxycinnamic acid 2-O-β-glucoside (cis-GMCA, 5.8%), narcissin (5.4%), and rutin (5.3%). Almost half of HIh phenolic content (14.7%) belonged to oxytroflavoside A (7-O-methylkaempferol-3-O-[3-hydroxy-3-methylglutaryl-(1→6)]-[α-rhamnopyranosyl-(1→2)]-β-galactopyranoside). Antioxidant properties of the Herniaria PEs were evaluated employing an experimental model of human blood plasma, exposed to the peroxynitrite-induced oxidative stress. The assays demonstrated significant reduction of oxidative damage to protein and lipid plasma components (estimated by measurements of 3-nitrotyrosine, protein thiol groups, thiobarbituric acid-reactive substances), and moderate protection of its non-enzymatic antioxidant capacity. Anti-inflammatory properties of the Herniaria PEs were evaluated In Vitro as inhibitory effects against cyclooxygenases (COX-1 and -2) and concanavalin A-induced inflammatory response of the peripheral blood mononuclear cells (PBMCs). None of the studied plants showed inhibitory effects on COXs but all purified extracts partly reduced the release of interleukin 2 (IL-2) and tumor necrosis factor-alpha (TNF-α) from PBMCs, which suggested their prospective ability to up-regulate inflammatory response of the cells. The purified extract from H. glabra turned out to be the most efficient suppressor of PBMCs’ inflammatory response. Additionally, cytotoxicity of purified Herniaria extracts on PBMCs was ruled out based on In Vitro studies.

Pulmonaria obscura and Pulmonaria officinalis Extracts as Mitigators of Peroxynitrite-Induced Oxidative Stress and Cyclooxygenase-2 Inhibitors-In Vitro and In Silico Studies

The Pulmonaria species (lungwort) are edible plants and traditional remedies for different disorders of the respiratory system. Our work covers a comparative study on biological actions in human blood plasma and cyclooxygenase-2 (COX-2) -inhibitory properties of plant extracts (i.e., phenolic-rich fractions) originated from aerial parts of P. obscura Dumort. and P. officinalis L. Phytochemical profiling demonstrated the abundance of phenolic acids and their derivatives (over 80% of the isolated fractions). Danshensu conjugates with caffeic acid, i.e., rosmarinic, lithospermic, salvianolic, monardic, shimobashiric and yunnaneic acids were identified as predominant components. The examined extracts (1–100 µg/mL) partly prevented harmful effects of the peroxynitrite-induced oxidative stress in blood plasma (decreased oxidative damage to blood plasma components and improved its non-enzymatic antioxidant capacity). The cellular safety of the extracts was confirmed in experimental models of blood platelets and peripheral blood mononuclear cells. COX-2 inhibitor screening evidently suggested a stronger activity of P. officinalis (IC₅₀ of 13.28 and 7.24 µg/mL, in reaction with synthetic chromogen and physiological substrate (arachidonic acid), respectively). In silico studies on interactions of main components of the Pulmonaria extracts with the COX-2 demonstrated the abilities of ten compounds to bind with the enzyme, including rosmarinic acid, menisdaurin, globoidnan A and salvianolic acid H.

Variability of sinapic acid derivatives during germination and their contribution to antioxidant and anti-inflammatory effects of broccoli sprouts on human plasma and human peripheral blood mononuclear cells

Broccoli sprouts represent a health-promoting food, rich in antioxidant and anti-inflammatory phytochemicals, among which sulfur compounds are most extensively investigated. In this study, the phenolics of broccoli sprouts (Brassica oleracea var. italica'Cezar') were examined for variability during germination and influence on the bioactivity of sprouts. In the sprouts germinated in darkness, 31 compounds were identified by UHPLC-PDA-ESI-MS³ (18 sinapic acid derivatives, 8 glucosinolates, and 5 flavonoids) with sinapoyl components (SADs) prevailing among polyphenols. The total SADs decreased during germination (down to 4.85 mg per g dw in 6-day-sprouts), but the concurrent changes in molecular structures of the leading compounds (sinapine was replaced by sinapate sugar esters and sinapic acid) increased the antioxidant capacity of the sprouts. The glucosinolate-depleted 6-day-sprout extract (34.2 mg SADs per g dw) effectively protected human plasma components against peroxynitrite-induced oxidative damage in vitro (reduced the levels of 3-nitrotyrosine, lipid hydroperoxides and thiobarbituric acid-reactive substances) and enhanced the non-enzymatic antioxidant status of plasma. It also downregulated the release of pro-inflammatory cytokines (TNF-α, IL-6) from LPS-stimulated human peripheral blood mononuclear cells and increased the production of IL-10, an anti-inflammatory mediator. The relevant activity parameters of sinapic acid indicated that SADs might be linked to the observed effects. The results support the application of broccoli sprouts in oxidative stress- and inflammation-related diseases and the role of SADs as their bioactive components next to glucosinolates.

Design of a Protein Motif Responsive to Tyrosine Nitration and an Encoded Turn-Off Sensor of Tyrosine Nitration

Tyrosine nitration is a protein post-translational modification that is predominantly non-enzymatic and is observed to be increased under conditions of nitrosative stress and in numerous disease states. A small protein motif (14-18 amino acids) responsive to tyrosine nitration has been developed. In this design, nitrotyrosine replaced the conserved Glu12 of an EF-hand metal-binding motif. Thus, the non-nitrated peptide bound terbium weakly. In contrast, tyrosine nitration resulted in a 45-fold increase in terbium affinity. Nuclear magnetic resonance spectroscopy indicated direct binding of nitrotyrosine to the metal and EF-hand-like metal contacts in this designed peptide. Nitrotyrosine is an efficient quencher of fluorescence. To develop a sensor of tyrosine nitration, the initial design was modified to incorporate Glu residues at EF-hand positions 9 and 16 as additional metal-binding residues, to increase the terbium affinity of the peptide with unmodified tyrosine. This peptide with a tyrosine at residue 12 bound terbium and effectively sensitized terbium luminescence. Tyrosine nitration resulted in a 180-fold increase in terbium affinity ( Kd = 1.6 μM) and quenching of terbium luminescence. This sequence was incorporated as an encoded protein tag and applied as a turn-off fluorescent protein sensor of tyrosine nitration. The sensor was responsive to nitration by peroxynitrite, with fluorescence quenched upon nitration. The greater terbium affinity upon tyrosine nitration resulted in a large dynamic range and sensitivity to substoichiometric nitration. An improved approach for the synthesis of peptides containing nitrotyrosine was also developed, via the in situ silyl protection of nitrotyrosine. This work represents the first designed, encodable protein motif that is responsive to tyrosine nitration.

Multifunctional Phytocompounds in Cotoneaster Fruits: Phytochemical Profiling, Cellular Safety, Anti-Inflammatory and Antioxidant Effects in Chemical and Human Plasma Models In Vitro

The work presents the results of an investigation into the molecular background of the activity of Cotoneaster fruits, providing a detailed description of their phytochemical composition and some of the mechanisms of their anti-inflammatory and antioxidant effects. GS-FID-MS and UHPLC-PDA-ESI-MS³ methods were applied to identify the potentially health-beneficial constituents of lipophilic and hydrophilic fractions, leading to the identification of fourteen unsaturated fatty acids (with dominant linoleic acid, 375.4–1690.2 mg/100 g dw), three phytosterols (with dominant β-sitosterol, 132.2–463.3 mg/100 g), two triterpenoid acids (10.9–54.5 mg/100 g), and twenty-six polyphenols (26.0–43.5 mg GAE/g dw). The most promising polyphenolic fractions exhibited dose-dependent anti-inflammatory activity in in vitro tests of lipoxygenase (IC₅₀ in the range of 7.7–24.9 μg/U) and hyaluronidase (IC₅₀ in the range of 16.4–29.3 μg/U) inhibition. They were also demonstrated to be a source of effective antioxidants, both in in vitro chemical tests (DPPH, FRAP, and TBARS) and in a biological model, in which at in vivo-relevant levels (1–5 μg/mL) they normalized/enhanced the nonenzymatic antioxidant capacity of human plasma and efficiently protected protein and lipid components of plasma against peroxynitrite-induced oxidative/nitrative damage. Moreover, the investigated extracts did not exhibit cytotoxicity towards human PMBCs. Among the nine Cotoneaster species tested, C. hjelmqvistii, C. zabelii, C. splendens, and C. bullatus possess the highest bioactive potential and might be recommended as dietary and functional food products.

γ-Pyrone compounds: flavonoids and maltol glucoside derivatives from Herniaria glabra L. collected in the Ternopil region of the Ukraine

The phytochemical investigation of the whole plant extracts of Herniaria glabra L. (Caryophyllaceae) led to the identification and isolation of four known flavonoids, one known and three undescribed maltol derivatives, and benzyl β-gentiobioside. The structures were established by extensive 1D and 2D NMR spectroscopic analyses, as well as HRESIMS data. For the first time in Herniaria genus, as well as in Caryophylaceae family the presence of apiorutin {quercetin 3-O-[(D-apio-β-d-furanosyl-(1 → 2)-O-[-α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside]} and licoagroside B {maltol 3-O-[6-O-(3-hydroxy-3-methylglutaroyl)]-β-d-glucopyranoside} were revealed. Additionally, antioxidant actions of apiorutin, rutin, narcissin (isorhamentin 3-O-β-d-rutinoside) and licoagroside B were assessed in human blood plasma, exposed to the peroxynitrite-induced oxidative stress in vitro. The isolates partly reduced oxidative (oxidation of thiol groups) and nitrative (tyrosine nitration) damage to blood plasma proteins, decreased plasma lipid peroxidation as well as enhanced the non-enzymatic antioxidant capacity of blood plasma. No cytotoxicity of the examined substances towards peripheral blood mononuclear cells was found.

Gasotransmitter Heterocellular Signaling

SIGNIFICANCE

The family of gasotransmitter molecules, nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S), has emerged as an important mediator of numerous cellular signal transduction and pathophysiological responses. As such, these molecules have been reported to influence a diverse array of biochemical, molecular, and cell biology events often impacting one another. Recent Advances: Discrete regulation of gasotransmitter molecule formation, movement, and reaction is critical to their biological function. Due to the chemical nature of these molecules, they can move rapidly throughout cells and tissues acting on targets through reactions with metal groups, reactive chemical species, and protein amino acids.

CRITICAL ISSUES

Given the breadth and complexity of gasotransmitter reactions, this field of research is expanding into exciting, yet sometimes confusing, areas of study with significant promise for understanding health and disease. The precise amounts of tissue and cellular gasotransmitter levels and where they are formed, as well as how they react with molecular targets or themselves, all remain poorly understood.

FUTURE DIRECTIONS

Elucidation of specific molecular targets, characteristics of gasotransmitter molecule heterotypic interactions, and spatiotemporal formation and metabolism are all important to better understand their true pathophysiological importance in various organ systems. Antioxid. Redox Signal. 26, 936-960.

Yunnaneic Acid B, a Component of Pulmonaria officinalis Extract, Prevents Peroxynitrite-Induced Oxidative Stress in Vitro

Our work reveals that the aerial parts of Pulmonaria officinalis L. are a new source of yunnaneic acid B. We studied antioxidant activity and cytotoxicity of this compound (1-50 μg/mL) and its contents in various plant extracts. This is the first study confirming the presence of yunnaneic acid B in P. officinalis L. and Pulmonaria obscura Dumort and hence in the Boraginaceae family. Determination of 1,1-diphenyl-2-picrylhydrazyl radical reduction and peroxynitrite-scavenging efficacy in inorganic experimental systems provided EC₅₀ values of 7.14 and 50.45 μg/mL, respectively. Then we examined the antioxidant action of yunnaneic acid B in blood plasma under peroxynitrite-induced oxidative stress in vitro. Yunnaneic acid B effectively diminished oxidative damage to blood plasma proteins and lipids. Furthermore, it was able to prevent the peroxynitrite-induced decrease in nonenzymatic antioxidant capacity of blood plasma. Additionally, cytotoxicity of yunnaneic acid B (at concentrations ≤50 μg/mL) toward peripheral blood mononuclear cells was excluded.

The susceptibility of plasma coagulation factor XI to nitration and peroxynitrite action

Coagulation factor XI is present in blood plasma as the zymogen, like other serine proteases of hemostatic system, but as the only coagulation factor forms 140-160kDa homodimers. Its activation is induced by thrombin, and a positive feedback increases the generation of the extra thrombin. Experimental and clinical observations confirm protective roles of factor XI deficiencies in certain types of thromboembolic disorders. Thromboembolism still causes serious problems for modern civilization. Diseases associated with the blood coagulation system are often associated with inflammation and oxidative stress. Peroxynitrite is produced from nitric oxide and superoxide in inflammatory diseases. The aim of the current study is to evaluate effects of nitrative stress triggered by peroxynitrite on coagulation factor XI in human plasma employing biochemical and bioinformatic methods. The amidolytic assay shows increase in factor XI activity triggered by peroxynitrite. Peroxynitrite interferes factor XI by nitration and fragmentation, which is demonstrated by immunoprecipitation followed by western blotting. Nitrated factor XI is even present in control blood plasma. The results suggest possible modifications of factor XI on the molecular level. Computer simulations show tyrosine residues as targets of peroxynitrite action. The modifications induced by peroxynitrite in factor XI might be important in thrombotic disorders.